Bone Staples Research Articles

Advanced machining of TiNiCo shape memory alloys for biomedical applications

Wire electro discharge machining (WEDM) is one of the most productive non-traditional machining processes. Complex shapes can be cut through the WEDM process. In the present study, attempts have been made to study the effects of various process parameters of WEDM such as pulse on time (T on), pulse off time (T off), servo voltage (SV), wire speed (WS) and servo feed (SF) on the material removal rate (MRR) and surface roughness (SR) for machining of TiNiCo shape memory alloys, traditionally used as bone staple material. Grey-relational-analysis-based entropy measurement methods were used for formulating a hybrid combination of optimisation methods, in order to investigate the input parameters of WEDM on the comprehensive performance of a bone staple material’s SR and MRR. Experiments were carried out by using response surface design (L-33), and the input parameters were ranked based on the grey relational grade. An experimental run was conducted using the optimal combination of input parameters of WEDM, which was obtained from the analysis. T on of 125 μs, T off of 42 μs, SV of 40 V, SF of 2180 machine units and WS of 4 m/min were obtained as the best combination of input process parameters for TiNiCo alloy.

Determination of patellar tendon length for anterior cruciate ligament reconstruction using an anteroposterior knee radiograph

Background/ObjectiveGraft-tunnel length mismatch is a common intraoperative technical problem for anterior cruciate ligament reconstruction (ACLR) using a bone-patellar tendon-bone graft (BPTB). The patella-to-condyle and the patella-to-notch distances are two measurements in an anteroposterior knee radiograph. The objective of this study was to evaluate the sensitivities, specificities and reliabilities of those 2 measurements for detecting patients who had a patellar tendon length exceeding 45 mm. MethodsPreoperative plain radiographs of patients who underwent ACLR with a BPTB graft were evaluated independently by two orthopaedic surgeons 3 times each at 2-weekly intervals. The sensitivities and specificities of the two measurements for detecting patients who have a patellar tendon length exceeding 45 mm were calculated. The optimal cutoff point was estimated using Youden index, and the receiver operating characteristic (ROC) curve and area under the curve (AUC) were evaluated with a 95% CI. As for the inter- and intra-rater reliabilities, intraclass correlation coefficients (ICC) were determined. ResultsOne hundred and twenty-seven patients with an average age of 29.5 years old were evaluated. The mean patellar tendon length was 41.3 ± 5.0 mm. Patients with a length more than 45 mm (20 patients, 16%) had significantly higher patella-to-condyle and patella-to-notch distances, and more frequent use of bone staples for distal graft fixation than patients with a length ≤ 45 mm. To detect patients with a patellar tendon length over 45 mm, the optimal cutoff point for the patella-to-condyle distance was set at 14.5 mm, which had a sensitivity of 80%, specificity of 71%, and AUC of 0.76. In the case of the patella-to-notch distance, the cutoff point of 5.5 mm had a sensitivity of 80%, specificity of 66%, and AUC of 0.73. The intra- and inter-rater reliabilities of the two measurements were excellent, with ICCs of over 0.90. ConclusionsPreoperative measurements of the patella-to-condyle and the patella-to-notch distances in AP knee radiographs can be valuable tools, with good sensitivities and specificities, for the determination of the patellar tendon length when using a BPTB graft for an ACLR. They had an acceptable level of discrimination capability and excellent reliability.

Comparative Study on Bending Strength of Metallic Bone Staple

Comparative Study on Bending Strength of Metallic Bone Staple

Managing Superficial Distal Medial Collateral Ligament Insufficiency in Primary Total Knee Arthroplasty Using Bone Staples.

Superficial medial collateral ligament (MCL) injury is an occasional intraoperative complication during total knee arthroplasty (TKA) that can lead to failure. Although previous studies have recommended complex repair or conversion to a constrained implant, the authors evaluated results of superficial distal MCL reapproximation using bone staples. Records of 31 patients who underwent staple reapproximation for superficial MCL avulsion from the tibial attachment during primary TKA from 2005 to 2015 were reviewed. They were compared with 685 patients who underwent uncomplicated TKA (primary control) and 18 who underwent revision TKA for instability (secondary control). Subjective knee instability was assessed with a patient questionnaire, and other end points included revision for instability or stiffness and manipulations under anesthesia. The authors prospectively collected Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale satisfaction scores. The mean follow-up was 2.6 years. No patients treated with staple repair required revision for instability, whereas two patients were revised in the primary control. Subjective instability was reported in 19.2% of staple repair patients compared with 24.2 and 46.2% of patients in the primary and secondary controls. The mean KOOS for the staple group was 71.7 points, 77.3 for the primary control, and 49.3 for the secondary. KOOSs for the staple group were 5.6 points lower than the primary control, but 22.4 points higher than the secondary. Staple reapproximation is a simple and effective method for repairing the superficial distal MCL in primary TKA. The rate of instability and functional outcomes was comparable to uncomplicated primary TKA.

Effect of machining process parameters on productivity rate and surface roughness of machined TiNiCo alloy

TiNiCo based shape memory alloy is an important alloy for biomedical applications such as bone staple due to their excellent biocompatibility, corrosion resistance, shape memory effect (SME) and pseudoelasticity (PE). Traditional machining of such kind of alloys is difficult due to their outstanding properties. Wire electro discharge machining (WEDM) is most suitable non-traditional machining process for machining of these alloys. Present study focuses on effect of WEDM process parameters on productivity rate and surface roughness. Pulse on time, servo voltage and wire speed were considered as WEDM process parameters with their five levels in the current study. Our observation exhibit that productivity rate and surface roughness increases with increasing pulse on time and both outputs decrease with increasing servo voltage while wire speed does not show much effect on productivity rate as well as surface roughness.

Prospective randomised comparison of femoral transfix versus endobutton with constant tibial fixation in hamstring tendon ACL reconstruction: a preliminary study

<p class="abstract"><strong>Background:</strong> The purpose of this study is to evaluate clinico radiological outcome of hamstring tendon ACL reconstruction using femoral Transfixation and Endobutton with identical Tibial fixation.</p><p class="abstract"><strong>Methods:</strong> A Prospective randomized clinical outcome study was done from January 2002 to June 2008, a total of 132 patients with quadruple hamstring ACL reconstruction using a femoral fixation group A Endobutton (n=68; median age=27.4) and group B with Transfix (n=64; median age=26.1) and identical Tibial fixation with Biointerference screw and bone staple were studied. Patients in each group had a clinical and radiological assessment at <3, 3-12, 12-24 and >24 months after surgery.<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean Lysholm Knee score has improved significantly with time within these groups but no difference on comparison between groups. Ninety percent of all patients had functionally normal or near normal International Knee Documentation Committee (IKDC) knee ligament ratings. IKDC Subjective Knee evaluation mean score has progressively increased significantly from pre op values of 37.58 and 36.55 to about 74.51 and 75.85 in group A and group B respectively. The tibial and femoral tunnels also showed widening of about 9.64% and 7.79% in group A as compared to 7.71% and 7.27% in group B at >24 months follow-up, which was statistically insignificant. MRI done in limited patients showed good graft incorporation in both groups.</p><p class="abstract"><strong>Conclusions:</strong> So keeping the tibial graft fixation constant, the two different femoral fixation methods, Endobutton and transfixation have not influenced in the clinical outcome in this short term preliminary study. But long term follow up of these is necessary to evaluate the significance of tunnel widening and its final outcome.</p>

Biomechanical comparison of pin and nitinol bone staple fixation to pin and tension band wire fixation for the stabilization of canine olecranon osteotomies.

To compare the initial biomechanical properties of olecranon osteotomies stabilized with intramedullary pins and a Nitinol bone staple to osteotomies stabilized with pin and tension band wire fixation. Ex vivo mechanical evaluation on cadaveric bones. Ten pairs of cadaveric forelimbs from skeletally mature Greyhounds with an olecranon osteotomy stabilized with either a pin and Nitinol bone staple or a pin and tension band wire. A single load to failure was applied to each specimen through the triceps tendon. Biomechanical properties were compared based on stiffness, yield load, and maximum load to failure and load at 2 mm of axial displacement. Specimens stabilized with the bone staple were biomechanically superior in all the variables tested. There was significantly greater stiffness (118.0 ± 25.9 N/mm versus 70.1 ± 40.4 N/mm; p = 0.005), yield load (319.0 ± 99.8 N versus 238.0 ± 42.5 N; p = 0.03), maximum load sustained (385.0 ± 99.2 N versus 287.0 ± 37.4 N; p = 0.009), and load at 2 mm of axial displacement (218.0 ± 51.5 N versus 138.0 ± 48.7 N; p = 0.002) in specimens stabilized with pins and a Nitinol bone staple than specimens stabilized with pin and tension band wire fixation. The pin and Nitinol bone staple construct provides a biomechanically superior alternative to pin and tension band wire fixation for stabilization of olecranon osteotomies, and its use warrants further clinical investigation.

A biomechanical analysis of tibial ACL reconstruction with graft length mismatch.

The incidence of graft length mismatch (GLM) during anterior cruciate ligament (ACL) reconstruction is reported to be up to 13%, with a rate of 20% when using bone-patellar tendon-bone (BPTB) allografts. Multiple techniques have been described to accommodate for the longer BPTB graft. As no study has compared the biomechanical properties of these methods (with cyclic loading), we evaluated the strength of four different surgical techniques used to accommodate for GLM during ACL reconstruction. A total of 32 fresh-frozen bovine tibiae and patellar tendons were divided into four groups based on the method of tibial graft fixation: (1) sutures tied over a post, (2) bone staples, (3) screws and washers, and (4) soft-tissue conversion with interference screw. Biomechanical testing was performed comparing the tensile properties of graft fixation techniques under cyclic loading. Ability to withstand 1500 cycles of load, the maximum tensile strength at load-to-failure, and the mode-of-failure were evaluated. Only group 4 had all grafts intact after 1500 loading cycles, while the other groups had one graft failure at 338 (group 1), 240 (group 2), and 309 (group 3) cycles. The highest mean load-to-failure was observed in group 3 at 762 ± 173 N, which was found to be significantly higher than the other groups. The mean loads to failure in groups 1-4 were 453 ± 86 N, 485 ± 246 N, 762 ± 173 N, and 458 ± 128 N. While there are multiple viable techniques for fixation of a BPTB graft in the case of GLM, this study demonstrated that direct screw fixation offers the strongest construct.

Posteromedially placed plates with anterior staple reinforcement are not successful in decreasing tibial slope in opening-wedge proximal tibial osteotomy.

To document the effectiveness of a novel technique to decrease tibial slope in patients who underwent a proximal opening-wedge osteotomy with an anteriorly sloped plate placed in a posteromedial position. The hypothesis was that posteromedial placement of an anteriorly sloped osteotomy plate with an adjunctive anterior bone staple on the tibia would decrease, and maintain, the tibial slope correction at a minimum of 6months following the osteotomy. All patients who underwent biplanar medial opening-wedge proximal tibial osteotomy with anterior staple augmentation to decrease sagittal plane tibial slope were included, and data were collected prospectively and reviewed retrospectively. Indications for decreasing tibial slope included medial compartment osteoarthritis with at least one of the following: ACL deficiency, posterior meniscus deficiency, or flexion contracture. Preoperative, immediate postoperative, and 6-month postoperative radiographs were reviewed. Twenty-one patients (14 males and 7 females) were included in the study with a mean age of 36.5years. Intrarater and interrater reliability of slope measurements were excellent at all time points (ICC≥0.94, ICC≥0.85). The osteotomy resulted in an average tibial slope decrease of 0.8 from preoperative (n.s.). At 6-month postoperative, average slope was not significantly different from time-zero postoperative slope (mean=+0.2°). The most important finding of this study was that posteromedial placement of an anteriorly angled osteotomy plate augmented with an anterior staple during a biplanar medial opening-wedge proximal tibial osteotomy did not decrease sagittal plane tibial slope. Whether a staple was effective in maintaining tibial slope from time zero to 6months postoperatively was unable to be assessed due to no significant change in tibial slope from the preoperative postoperative states. The results of this study note that current osteotomy plate designs and surgical techniques are not effective in decreasing sagittal plane tibial slope. IV.

Assessing the performance characteristics and clinical forces in simulated shape memory bone staple surgical procedure: The significance of SMA material model

This work is focused on the detailed computer simulation of the key stages involved in a shape memory alloy (SMA) osteosynthesis bone stapling procedure. To this end, a recently developed three-dimensional constitutive SMA material model was characterized from test data of three simple uniaxial-isothermal-tension experiments for powder metallurgically processed nickel-rich NiTi (PM/NiTi-P) material. The calibrated model was subsequently used under the complex, thermomechanical loading conditions involved in the surgical procedure using the body-temperature-activated PM/NiTi-P bone staple. Our aim here is to assess the immediate and post-surgical performance characteristics of the stapling operation using the material model. From this study: (1) it was found that adequate compressive forces were developed by the PM/NiTi-P bone staple, with the tendency of this force to even increase under sustained thermal loading due to the intrinsic “inverse relaxation phenomena” in the SMA material, (2) the simulation results correlated well with those from experimental measurements, (3) the body-temperature-activated PM/NiTi-P staple was proved to be clinically viable, providing a stable clamping force needed for speedy coaptation of the fractured bones, and (4) these realistic assessments crucially depend on the use of suitable and comprehensive SMA material models.

Surgical Stabilization of the Medial Capsulo-Ligamentous Envelope in Total Knee Arthroplasty

This study will evaluate an alternative method in which a four prong bone staple was used to repair the medial collateral ligament following over-release or avulsion injuries in (#6) cases during a total knee arthroplasty. The use of a four prong bone staple to repair medial collateral ligament injuries status post total knee replacement will provide satisfactory results with respect to post-operative knee stability and range of motion. Our retrospective review revealed that all six patients improved with regards to range of motion following the total knee arthroplasty. We feel that repair of the medial collateral ligament with a four-prong bone staple is a viable option after an over-release or avulsion injury sustained during a total knee arthroplasty.

A novel technique for removal of bone staples

Bone staples are commonly used in knee epiphysiodesis. Removal of staples years later can be challenging, particularly where bony over-growth has occurred. Dissection and stripping of bone during removal risks damage to the surrounding structures. Our simple technique using common orthopaedic instruments allows safe and effective retrieval of bone staples. A bone hook is applied under the bone staple and an osteotome is introduced horizontally through the handle of the bone hook. Gentle backward blows are applied on to the osteotome handle with a mallet (analogous to using a slap hammer), lifting staples off the bone in a controlled manner (Fig 1). Figure 1 Bone hook inserted under staple, with osteotome passed horizontally through the handle of the bone hook. Mallet used to apply gentle blows backwards on to the osteotome handle.

A novel technique for removal of bone staples

A novel technique for removal of bone staples

Traumatic Sternomanubrial Instability and Arthrosis: A Case Report and Review.

Sternomanubrial instability is a rare clinical finding, with very limited evidence characterizing any progression to degenerative joint changes. Because of its infrequent nature, there is not much information on this condition in the literature. The sternomanubrial joint has a symphyseal-type articulation, with both sides of the joint covered with hyaline cartilage. A small, well-fixed fibrocartilage disc exists between the two joint surfaces and acts to stabilize the joint additionally. The sternomanubrial joint is strengthened by anterior and posterior fibrous ligaments, which extend across the joint from the manubrium to the body. In the normal joint, minimal motion is present. Sternomanubrial injury is generally related to high-energy trauma, and is usually associated with a fracture, dislocation, or a fracture-dislocation of the sternum and/or manubrium1-4. Some case reports exist on the development of a painful degenerative sternomanubrial joint after a history of minor trauma5,6. With little published data, it is a challenge to treat a patient with sternomanubrial pain. If there is a displaced fracture, dislocation, or fracture-dislocation, treatment is more straightforward. As with most fractures or dislocations that cannot be managed by closed means, operative reduction and stabilization is currently recommended3. However, options for managing the patient with an arthritic sternomanubrial joint are less clearly established. Conservative measures, including physical therapy and anti-inflammatory medication, have poor reported efficacy in improving outcomes, and surgical treatment, including arthrodesis, is often necessary2,6,7. Fixation techniques for arthrodesis have utilized sutures, bone staples, and plate/screw constructs, but because of the limited number of patients, no superior technique has emerged. We present a patient with chronic sternomanubrial instability and pain after an athletic injury. He was informed that data concerning the case would be submitted for publication, and he provided consent. …

Preparation and Characterization of Nitinol Bone Staples for Cranio-Maxillofacial Surgery

The aim of this work was to form NiTi and TiNiCo body temperature activated and superelastic staples for clinical joining of mandible and face bone fractures. The alloys were obtained by VIM technique. Hot and cold processing was applied to obtain wires of required diameters. The martensitic transformation was studied by DSC, XRD, and TEM. The shape memory effects were measured by a bend and free recovery ASTM F2082-06 test. The superelasticity was recorded in the tension stress-strain and by the three-point bending cycles in an instrument equipped with a Hottinger force transducer and LVDT. Excellent superelastic behavior of TiNiCo wires was obtained after cold working and annealing at 400-500 °C. The body temperature activated shape memory staples were applied for fixation of mandibular condyle fractures. In experiments on the skull models, fixation of the facial fractures by using shape memory and superelastic staples were compared. The superelastic staples were used in osteosynthesis of zygomatico-maxillo-orbital fractures.

The Effect of Height on Tibial Strain During Drop Landings

During landing, the human body is required to absorb impact forces throughout its tissues. Muscle and connective tissue dissipate much of this force. A portion of the impact is delivered to the bones. Repetitive forces acting on the tibia during landing can cause microfractures which may lead to stress fracture. It is difficult to quantify bone strain through invasive measure such as bone staple. PURPOSE: To calculate changes in bone strain during landing using a noninvasive approach by integrating a finite element tibia in a musculoskeletal model. METHODS: A musculoskeletal model representing a healthy male subject (22 years, 78.6 kg, 1.85 m) was created. A flexible tibia, created from a CT scan of the subject's right tibia, was included in the model. Motion capture data were collected while the subject performed drop landings from three separate heights (26, 39, and 52 cm) and served as inputs to perform dynamic simulations. Surface electromyography and joint angle data were compared to their simulation using a cross correlation. Maximum magnitudes of principal and maximum shear strain were computed. RESULTS: Strong cross-correlation coefficients (CCC > 0.87) were found between recorded and simulated lower extremity joint angles. Recorded activity in the vastus lateralis, vastus medialis, and the tibialis anterior agreed strongly with the model (CCC > 0.75). Weaker relationships existed in the gastrocnemius, hamstring, and soleus, which may be due to co-contraction. Maximum principal strain increased with height in 26cm (595 ± 136 μstrain), 39cm (879 ± 134 μstrain), and 52cm (1077 ± 108 μstrain). Minimum principal strain negatively increased with height in 26cm (-593 ± 86 μstrain), 39cm (-645 ± 35 μstrain), and 52cm (-769 ± 33 μstrain) landings. Maximum shear strain followed the same increasing trend in 26cm (592 ± 111 μstrain), 39cm (760 ± 83 μstrain), and 52cm (899 ± 98 μstrain) landings. CONCLUSION: The simulated results showed reasonable agreement with the recorded lower extremity joint angles and muscle activities. The calculated tibial strains were in reasonable agreement with the literature. This study demonstrates a valid non-invasive method of simulating landing movement and computing tibial strain produced during landing movements. Supported by DoD #W81XWH-08-1-0587 and BSU 2009 ASPiRE.

A Thermo-Mechanical Behavior Simulation of A NiTi Staple Used for the Correction of Idiopathic Scoliosis

In order to treat scoliosis, a thermo-mechanical behavior study of shape memory alloy bone staple has been proposed. A pre-stretched shape-memory-alloy bone staple, which has been heated above the transition temperature, provides greater compressive force upon insertion between two vertebrae and allows the control of idiopathic scoliosis development. Until now, the optimal design has not been reached due to the lack of appropriate design tools for shape memory alloy devices. In this paper, a shape memory alloy bone staple model is proposed by developing a user subroutine UMAT based on Boyd et al. unified thermodynamic shape memory alloy constitutive law using the finite element analysis software, ABAQUS. The numerical results for superelastic and shape memory effect under the tensile and three-point bending tests are presented. Simulations of the shape memory effects and force generation of the shape memory alloy staple are also shown.

Das besondere Instrument – Cup & Cone-Fräsen zur Arthrodese des Großzehengrundgelenks

Individual optimized positioning of arthrodesis of the first metatarsophalangeal joint (fusion of MTP1 joint) as well as presumable shortage of the first ray using precalculated osteotomies often unpredictable. Preparation of accurately fitting broad contact surfaces for MTP1 joint fusion with maximum flexibility of intraoperative decision-making for an optimized position. ADVANTAGES OF THE INSTRUMENTS: Semi-open or open systems of motor powered Cup & Cone reamers allow removal of remaining cartilage intended for MTP1 joint fusion with checkable shortage of the first ray, creation of exactly congruent concave-convex surfaces for an optimized position of MTP1 joint fusion. Medial longitudinal incision for exposure of MTP1 joint. Removal of osteoarthrophytes, cartilage, and sclerotic bone from the first metatarsal head and the base of proximal phalanx, using a motorized Cup & Cone reamer set over axially directed guide wires to cancellous bone. Provisional positioning of the fragments in an optimized position. Clinical and fluoroscopic control. Definite internal fixation using a plantar lag screw and superelastic bone staples or a locking-plate system. Allows the surgeon to prepare congruent and broad metatarsal and phalangeal cancellous bone surfaces for an optimized position of MTP1 joint fusion. Reamer-induced thermal damage and osteonecrosis were not encountered.

Arthroscopic Removal of a Broken Bone Staple Occurring 24 Years After Insertion That Presented as Lateral Joint Line Pain and Joint Locking

Arthroscopic Removal of a Broken Bone Staple Occurring 24 Years After Insertion That Presented as Lateral Joint Line Pain and Joint Locking

Design Considerations for Nitinol Bone Staples

The use of Nitinol in orthopedic staples has a long, successful history beginning with their first commercial introduction in the early 1980s. Nitinol bone staples are generally inserted through a process of being chilled, opened, and inserted into predrilled holes. Upon insertion, they recover their preprogrammed shape either through springing back after removal of a constraint (using superelasticity) or thermal triggering (using thermal shape memory). In general, Nitinol bone staples fall into one of three categories: (1) those which are superelastic at room temperature, (2) those which recover their shape upon heating to body temperature, or (3) those which recover their shape upon heating above body temperature with the application of an external heat source. These three different design approaches—room temperature superelastic, body temperature activated, and heat activated—each have different performance characteristics. A version of the heat activated staple that uses a controlled heat source appears to have the best combination of clinical forces and procedural control.